Them mesh doesn't follow the rig in pose mode

First off, english is not my first language and im really new to blender, so I can have some troubles with explaining things.

My problem is that when i parent the bones to the mesh, the mesh in pose mode doesn’t follow the bones. They move separately when I rotate the bones. Everything seems to be fine besides that the armature modifier’s name is highlighted in red.

I feel like it needs a really simple solution but I can’t figure it out.